In most known pantograph arm wiper systems the wiper blade had to be especially designed for this purpose, i.e. one of the rods of the pantograph was rigidly secured to the medium portion of the superstructure of the wiper blade and the evident drawback was that wiper blades which were designed for pantograph arms could not be used with conventional wiper arms. The result was an increase of the stocks in the warehouses of the manufacturers and of the dealers.
In other known pantograph arm wiper systems the pivot axis which is perpendicular to the windshield, and about which the wiper blade must be capable of rotating, is formed by a pin which is rigidly attached to the medium portion of the superstructure of the wiper blade and, therefore, has the same drawback as the one mentioned in the preceding paragraph.
Generally speaking a disadvantage of all the known pantograph arm wiper systems is that their total height above the windshield is too great. Said height is very important in all the cases where, in its rest position, the whole wiper system is located beneath the hood of the vehicle. In such circumstances each millimeter is of importance.
U.S. Pat. No. 3,893,204 and German (DE) Patent Application No. 28 30 507 show pantograph arm wiper systems wherein the wiper blade no longer has to be especially designed for use with a pantograph arm, thus eliminating the above mentioned stocking problems.
However, the two systems described in these documents have the disadvantage that even if the pantograph arm can be easily dismounted from the wiper blade this is not true for dismounting the connecting device or connector from the pantograph arm. Indeed this can only be done practically by destroying one or the other part of the arm/connector assembly.
The major disadvantage of said two systems is their relatively prominent or excessive height above the windshield, height which is due to the fact that the two arms of the pantograph are located not only one above the other, but also both above the superstructure of the wiper blade.
Another disadvantage of most known pantograph arm wiper systems is the fact that if the wiper blade is not symmetrical with respect to its transverse medium plane it is necessary to manufacture one wiper blade for the left hand drive vehicles and a modified one for the right hand drive vehicles. Indeed in one case the rod of the pantograph which is rigidly attached to the superstructure of the wiper blade is located on one side of the blade and in the other case said rod of the pantograph is located on the other side of the blade.